1) Field of the Invention
The field of this invention relates to detection apparatuses and more particularly to an apparatus which is designed to detect the creation of a heat seal between a plurality of abutting plastic sheets.
2) Description of the Prior Art
The present invention has to do with the forming of seals between thin sheets of plastic. These seals are commonly formed to form plastic bags with these bags being filled with some substance. This filling of the bags is accomplished automatically with automatic bag filling equipment. Common types of such substances could be a powder liquid or a semi-liquid slurry. Within the food industry typical bags could be with a tomato sauce or tomato type of slurry.
Within the food industry, a tomato slurry would be formulated within a mixing vat. From the mixing vat, the tomato slurry is conducted to a hopper. On each side of the hopper there is moved a sheet material plastic, with underneath the hopper these plastic sheets abuttingly joining together. A sealing device is then to be used to seal the plastic sheets forming a horizontal seal with separate sealing devices being used to form vertical seals at the sides of the sheet material members. The net result is, a bag is formed and immediately after formulation of the bag a prescribed weighted amount of the slurry is discharged from the hopper into the now filled bag. The sheet material members are now moved a short distance and the resealing process continues forming another bag and so forth. After the bag is formed, sealed at both the upper and the lower ends, a cutter is used to separate each bag from its directly adjacent bag. The now separated bag is to be shipped to the desired location where the tomato slurry is to be utilized such as at a store that makes pizzas.
At times, during the heat sealing process, a small amount of residue of the tomato slurry may be located in the area where the heat sealing incurs. If such is the case, an imperfect seal will be produced. It is important to seal the bag from air to eliminate any possible generation of undesireable bacteria as well as premature deterioration of the food within the bag.
The automated equipment that is utilized in the generation of the bags of food produces such in a rather rapid manner. In the past, there have been utilized people whose job is to physically observe seals on the bags and make a determination if any bag has an imperfect seal. Such manual observation is effective for a short period of time. However, over a period of hours, the individual or individuals involved which do the observing become rather inefficient at discovering the imperfect seals. In the way that the bags are filled automatically there should be achieved some way to automatically ascertain whether the seals of the bags are satisfactory.